LEP Shines Light on Dark Matter

TL;DR

This paper uses LEP data to set new constraints on dark matter interactions with electrons, providing competitive and systematic-uncertainty-free limits that complement other detection methods, especially for light dark matter particles.

Contribution

The study presents novel constraints on dark matter-electron couplings from LEP mono-photon data, covering models with light mediators and offering the strongest limits in certain mass ranges.

Findings

LEP data constrains dark matter-electron couplings effectively.

Limits are stronger than some astrophysical observations for specific mass ranges.

Provides the tightest bounds on spin-dependent cross sections for certain models.

Abstract

Dark matter pair production at high energy colliders may leave observable signatures in the energy and momentum spectra of the objects recoiling against the dark matter. We use LEP data on mono-photon events with large missing energy to constrain the coupling of dark matter to electrons. Within a large class of models, our limits are complementary to and competitive with limits on dark matter annihilation and on WIMP-nucleon scattering from indirect and direct searches. Our limits, however, do not suffer from systematic and astrophysical uncertainties associated with direct and indirect limits. For example, we are able to rule out light (< 10 GeV) thermal relic dark matter with universal couplings exclusively to charged leptons. In addition, for dark matter mass below about 80 GeV, LEP limits are stronger than Fermi constraints on annihilation into charged leptons in dwarf spheroidal galaxies. Within its kinematic reach, LEP also provides the strongest constraints on the spin-dependent direct detection cross section in models with universal couplings to both quarks and leptons. In such models the strongest limit is also set on spin independent scattering for dark matter masses below ~4 GeV. Throughout our discussion, we consider both low energy effective theories of dark matter, as well as several motivated renormalizable scenarios involving light mediators.